Cleaning sheet and process for cleaning substrate treatment device using same

ABSTRACT

A cleaning sheet comprising: a cleaning layer; and a protective film treated with a releasing agent comprising a silicone, the protective film being provided as a separator on at least one side of the cleaning layer, wherein an amount of silicone attached to the cleaning layer when the separator is peeled off from the cleaning layer is 0.005 g/m 2  or less as calculated in terms of polydimethylsiloxane.

TECHNICAL FIELD

The present invention relates to a sheet for cleaning a device and moreparticularly to a cleaning sheet and cleaning process for substratetreatment device apt to be easily damaged by foreign matters such assemiconductor or flat panel display producing device and semiconductoror flat panel display inspection device.

BACKGROUND ART

A substrate treatment device conveys various conveyance systems andsubstrates which are in physical contact with each other. During thisprocedure, when foreign matters are attached to the substrate orconveyance system, the subsequent substrates can be successivelycontaminated, making it necessary to suspend the operation of the deviceand clean the device at regular intervals. This brought forth a problemthat the working efficiency is lowered or much labor is required. Inorder to solve these problems, a process which comprises conveying asubstrate having an adhesive material fixed thereto to clean awayforeign matters attached to the interior of the substrate treatmentdevice (Japanese Patent Laid-Open No. 1998-154686) and a process whichcomprises conveying a tabular member to remove foreign matters attachedto the back surface of the substrate (Japanese Patent Laid-Open No.1999-87458) have been proposed.

DISCLOSURE OF THE INVENTION

The process which comprises conveying a substrate having an adhesivematerial fixed thereto to clean away foreign matters attached to theinterior of the substrate treatment device is an effective process forovercoming the aforementioned problems. However, in accordance with thisprocess, since an adhesive material is used as a cleaning layer, it islikely that the adhesive material can be so firmly bonded to the contactarea of the device that it cannot be peeled off the contact area, makingit impossible to certainly convey the substrate. This problem isparticularly remarkable when the chuck table of the device comprises avacuum suction mechanism.

Further, the process which comprises conveying a tabular member toremove foreign matters can perform conveyance without any troubles butis disadvantageous in that the removing capacity, which is important, ispoor.

Moreover, it is desired that the cleaning sheet for use in the removalof these foreign matters be composed of a cleaning layer which causes nocontamination on the conveying site, etc. in the substrate treatmentdevice. The separator to be stuck to the cleaning layer needs to begiven similar consideration. In other words, the cleaning sheet isnormally arranged such that the separator is stuck to the surface of thecleaning layer to protect the surface of the cleaning layer or improvethe handleability thereof. As this separator there is often used apolyester film or the like which has been release-treated with silicone,wax or the like from the standpoint of releasability.

However, when the aforementioned separator is peeled off the cleaninglayer during use, the release treatment such as silicone and wax movesto the cleaning layer. When this cleaning sheet is conveyed into thesubstrate treatment device in an attempt to remove foreign matters, theaforementioned release treatment transferred is attached to theconveying site, etc. in the device, contaminating the device todisadvantage.

Therefore, it has been heretofore practiced to use a cleaning layersurface protective film made of a polyolefin-based resin instead of theaforementioned separator. This kind of a film itself can exhibit asufficient releasability even without being release-treated withsilicone, wax or the like and thus can prevent contamination of thedevice. However, in the case where the cleaning sheet is used in adevice having a temperature of about 80° C. or like cases, a problemarises that the interior of the device is still contaminated for thereason that various additives which have been added during thefilm-forming of the polyolefin-based resin move to the cleaning layerand then are gasified or react with the remaining gas in the device.

The first and second inventions have an object of providing a cleaningsheet which can be certainly conveyed through the substrate treatmentdevice to simply and certainly remove foreign matters attached thereto.

Further, referring to the aforementioned process for the production ofthe conveying member with cleaning function, in the case where acleaning sheet is stuck to a conveying member such as substrate toproduce a cleaning member, when a cleaning sheet having a size greaterthan the shape of the conveying member is stuck to the conveying member,and then cut along the contour of the conveying member (hereinafterreferred to as “direct cutting process”), chips are produced from thecleaning layer, etc. during sheet cutting and then attached to thecleaning member and the device to disadvantage. Further, in the casewhere a cleaning label sheet which has been previously worked into amember form is stuck to a conveying member to produce a cleaning member(hereinafter referred to as “precutting process”), the production ofchips during label working can be suppressed as compared with directcutting process, but the adhesive of the cleaning layer protrudes fromthe cutting section during label cutting, making it likely that theadhesive can be attached to the end of the label. Moreover, in the casewhere as the adhesive there is used a polymerization-curing adhesive,when curing is effected after sheet cutting, the adhesive at the cut endundergoes malcuring due to oxygen inhibition, possibly causingcontamination on the contact site in the substrate treatment device.

In addition, in the case where the label sheet is punched, the cleaninglabel is continuously prepared in the form of separator of continuouslength with an ordinary adhesive interposed therebetween. However, inthis case, when as the cleaning layer there is used an adhesive which ispolymerized and cured when given an activation energy, the cleaninglayer undergoes hardening and shrinkage, causing the label itself to beeasily peeled off the separator. When the peel adhesion between theseparator and the adhesive is small, the cleaning label can be peeledoff the separator. Further, when the release layer of the separator forretaining the label is unstable, the peel adhesion of the release layercan change during storage or the constituents of the release layer canmove to the surface of the adhesive layer, deteriorating the adhesiveproperties of the label. In worst cases, the label can be peeled off theconveying member during the use of the cleaning member, causing errorsin the device.

In addition, in the case where curing is effected before sheet punching,particularly in the case where a silicone releasing agent is used as arelease film for the surface protection of the cleaning layer, saidsilicone component can move to the surface of the cleaning layer.

Under these circumstances, the third invention has an object ofproviding a label sheet with cleaning function which can be certainlyconveyed through the substrate treatment device to simply and certainlyremove foreign matters attached to the device without causing peeling ofcleaning label off separator in precutting process and is excellent inage stability and adhesive properties of label.

Further, under these circumstances, the fourth invention has an objectof providing a process for the production of a label sheet with cleaningfunction which allows a substrate to be certainly conveyed through thesubstrate treatment device, making it possible to simply and certainlyremove foreign matters attached to the interior of the device, andcauses neither malpunching during sheet punching nor malcuring ofadhesive in precutting process.

The inventors made extensive studies of the aforementioned objects. As aresult, it was found that the use of the first invention which is aprotective film release-treated with a silicone-based releasing agentlaminated as a separator wherein the amount of silicone attached to saidcleaning layer when said separator is peeled off said cleaning layer is0.005 g/m² or less as calculated in terms of polydimethylsiloxane andthe coated amount of silicone on said separator is 0.1 g/m² or less ascalculated in terms of polydimethylsiloxane as a protective film forprotecting said cleaning layer when the interior of a device is cleanedto remove foreign matters attached thereto by conveying a conveyingmember such as sheet having a cleaning layer and substrate having such asheet fixed thereto into the device makes it possible to certainlyprevent problems of contamination on the device due to separator andpeel foreign matters simply and certainly without causing theaforementioned problems. Thus, the present invention has been workedout.

As the second invention, it was found that the use of an untreatedprotective film made of a polyolefin-based resin laminated as aseparator wherein the sum of the amount of a heat deteriorationinhibitor and a lubricant incorporated in the protective film is lessthan 0.01 parts by weight based on 100 parts by weight ofpolyolefin-based resin as the aforementioned protective film forprotecting the cleaning layer makes it possible to certainly preventproblems of contamination on the device due to separator and peelforeign matters simply and certainly without causing the aforementionedproblems. Thus, the present invention has been worked out.

As the fourth invention, the inventors made extensive studies toaccomplish the aforementioned objects. As a result, it was found thatthe use of a precutting process for the production of a label sheet withcleaning function comprising a cleaning layer made of an adhesive whichundergoes polymerization and curing when given an activation energywhich comprises peeling a first release film of the cleaning layerbefore the polymerization curing reaction of the adhesive of thecleaning layer, subjecting the cleaning layer to polymerization curingunder conditions that there are no substantial effect of oxygen,protecting the surface of said cleaning layer by a second release film,and then cutting the label makes it possible to produce a label sheetwith cleaning function which can remove foreign matters simply andcertainly without causing the aforementioned problems. Thus, the presentinvention has been worked out.

In other words, the first essence of the present invention concerns acleaning sheet comprising a cleaning layer and a protective filmrelease-treated with a silicone-based releasing agent laminated as aseparator on at least one side thereof, characterized in that the amountof silicone attached to said cleaning layer when said separator ispeeled off said cleaning layer is 0.005 g/m² or less as calculated interms of polydimethylsiloxane, a cleaning sheet comprising a cleaninglayer and a protective film release-treated with a silicone-basedreleasing agent laminated as a separator on at least one side thereof,characterized in that as said separator there is used a separator coatedwith a silicone in an amount of 0.1 g/m² or less as calculated in termsof polydimethylsiloxane, a cleaning sheet comprising a cleaning layerand a protective film release-treated with a silicone-based releasingagent laminated as a separator on at least one side thereatcharacterized in that the amount of silicone attached to said cleaninglayer when said separator is peeled off said cleaning layer is 0.005g/m² or less as calculated in terms of polydimethylsiloxane and there isprovided an ordinary adhesive layer provided on the other side of saidcleaning layer, a cleaning sheet comprising a cleaning layer and aprotective film release-treated with a silicone-based releasing agentlaminated as a separator on at least one side thereof, characterized inthat as said separator there is used a separator coated with a siliconein an amount of 0.1 g/m² or less as calculated in terms ofpolydimethylsiloxane and there is provided an ordinary adhesive layerprovided on the other side of said cleaning layer, a cleaning sheetcomprising a cleaning layer provided on at least one side of a backingand a protective film release-treated with a silicone-based releasingagent laminated as a separator thereon, characterized in that the amountof silicone attached to said cleaning layer when said separator ispeeled off said cleaning layer is 0.005 g/m² or less as calculated interms of polydimethylsiloxane, a cleaning sheet comprising a cleaninglayer provided on at least one side of a backing and a protective filmrelease-treated with a silicone-based releasing agent laminated as aseparator thereon, characterized in that as said separator there is useda separator coated with a silicone in an amount of 0.1 g/m² or less ascalculated in terms of polydimethylsiloxane, a cleaning sheet comprisinga cleaning layer provided on at least one side of a backing, an ordinaryadhesive layer provided on the other side of said backing and aprotective film release-treated with a silicone-based releasing agentlaminated as a separator on at least the surface of said cleaning layer,characterized in that the amount of silicone attached to said cleaninglayer when said separator is peeled off said cleaning layer is 0.005g/m² or less as calculated in terms of polydimethylsiloxane, a cleaningsheet comprising a cleaning layer provided on at least one side of abacking, an ordinary adhesive layer provided on the other side of saidbacking and a protective film release-treated with a silicone-basedreleasing agent laminated as a separator on at least the surface of saidcleaning layer, characterized in that as said separator there is used aseparator coated with a silicone in an amount of 0.1 g/m² or less ascalculated in terms of polydimethylsiloxane, etc.

The second essence of the present invention concerns a cleaning sheetcomprising an untreated protective film made of a polyolefin-based resinlaminated as a separator on at least one side of a cleaning layer,wherein the sum of the amount of a heat deterioration inhibitor and alubricant incorporated in this protective film is less than 0.01 partsby weight based on 100 parts by weight of polyolefin-based resin, acleaning sheet comprising an untreated protective film made of apolyolefin-based resin laminated as a separator on one side of acleaning layer, wherein the sum of the amount of a heat deteriorationinhibitor and a lubricant incorporated in this protective film is lessthan 0.01 parts by weight based on 100 parts by weight ofpolyolefin-based resin and there is provided an ordinary adhesive layerprovided on the other side of said cleaning layer, a cleaning sheetcomprising a cleaning layer provided on at least one side of a backingand an untreated protective film made of a polyolefin-based resinlaminated as a separator on the surface of said cleaning layer, whereinthe sum of the amount of a heat deterioration inhibitor and a lubricantincorporated in this protective film is less than 0.01 parts by weightbased on 100 parts by weight of polyolefin-based resin, a cleaning sheetcomprising a cleaning layer provided on one side of a backing, anordinary adhesive layer provided on the side of said backing and anuntreated protective film made of a polyolefin-based resin laminated asa separator on at least the surface of said cleaning layer, wherein thesum of the amount of a heat deterioration inhibitor and a lubricantincorporated in this protective film is less than 0.01 parts by weightbased on 100 parts by weight of polyolefin-based resin, a cleaningsheet, wherein said protective film is free of heat deteriorationinhibitor and lubricant, etc.

The third essence of the present invention concerns a label sheet withcleaning function comprising a cleaning layer provided on one side of abacking with its surface protected by a release film and wherein theother side of said backing is continuously provided peelably apart fromeach other on a separator of continuous length with an ordinary adhesivelayer interposed therebetween, characterized in that the 180° peeladhesion required to peel said separator off said ordinary adhesivelayer is 0.05 N/50 mm or more, a label sheet with cleaning functioncomprising a cleaning layer provided on one side of a backing with itssurface protected by a release film wherein the other side of saidbacking is continuously provided peelably apart from each other on aseparator of continuous length with an ordinary adhesive layerinterposed therebetween, characterized in that as said separator thereis used a separator having a percent residual adhesion of 85% or more asdetermined by No. 31 B tape produced by NITTO DENKO CORPORATION, a labelsheet with cleaning function, wherein the tensile modulus of saidcleaning layer (according to JIS K7127 testing method) is 10 Mpa ormore, a label sheet with cleaning function, comprising a cleaning sheethaving a cleaning layer made of a curing adhesive containing apressure-sensitive adhesive polymer, a polymerizable unsaturatedcompound having one or more unsaturated double bonds per molecule and apolymerization initiator, a label sheet with cleaning function, whereinthe pressure-sensitive adhesive is an acrylic polymer comprising a(meth)acrylic acid alkylester as a main monomer, a label sheet withcleaning function, wherein the polymerization initiator is aphotopolymerization initiator and the cleaning layer is a photo-setting(photo-curing) adhesive layer, etc.

The fourth essence of the present invention concerns a process for theproduction of a label sheet with cleaning function comprising a cleaninglayer made of an adhesive which undergoes polymerization and curing whengiven an activation energy on one side of a backing with the surfacethereof protected by a release film wherein the other side of saidbacking is peelably provided on a separator with an ordinary adhesivelayer interposed therebetween, characterized in that the amount offoreign matters having a size of 0.2 μm or more transferred from thecleaning layer of the label sheet thus obtained to a silicon wafer is 20pieces/in² or less, a process for the production of a label sheet withcleaning function comprising a cleaning layer made of an adhesive whichundergoes polymerization and curing when given an activation energy onone side of a backing with the surface thereof protected by a releasefilm wherein the other side of said backing is peelably provided on aseparator with an ordinary adhesive layer interposed therebetween, whichcomprises peeling a first release film of the cleaning layer before thepolymerization curing reaction of the adhesive of said cleaning layer,subjecting the cleaning layer to polymerization curing under conditionsthat there are no substantial effect of oxygen, protecting the surfaceof said cleaning layer by a second release film, and then punching thesheet into a label form, a process for the production of a label sheetwith cleaning function, wherein the first release film which protectsthe surface of the cleaning layer before the polymerization curingreaction of the adhesive of the cleaning layer is a film withsilicone-based releasing agent, a process for the production of a labelsheet with cleaning function, wherein the tensile modulus of thecleaning layer during punching of the sheet into a label form (accordingto JIS K7127 testing method) is 10 MPa or more, a process for theproduction of a label sheet with cleaning function, wherein the cleaninglayer is a curing adhesive containing a pressure-sensitive adhesivepolymer, a polymerizable unsaturated compound having one or moreunsaturated double bonds per molecule and a polymerization initiator, aprocess for the production of a label sheet with cleaning function,wherein the pressure-sensitive adhesive polymer is an acrylic polymercomprising a (meth)acrylic acid and/or (meth)acrylic acid alkylester asa main monomer, a process for the production of a label sheet withcleaning function, wherein the polymerization initiator is aphotopolymerization initiator and the cleaning layer is a photo-settingadhesive layer, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating an embodiment of the label sheet withcleaning function of the present invention.

FIG. 2 is a sectional view taken along the line a-a of FIG. 1.

The reference numbers in the figure are as follows.

1: Separator, A: Cleaning label, 2: Backing, 3: Cleaning layer, 4:Release film, 5: Ordinary adhesive layer

The first cleaning sheet of the present invention comprises a separatorrelease-treated with a silicone-based releasing agent as a protectivefilm for protecting the surface of the cleaning layer. The saidseparator to be laminated on the said cleaning layer needs to meet therequirements that the amount of silicone attached to the said cleaninglayer when the said separator is peeled off the said cleaning layer be0.005 g/m², particularly preferably 0.003 g/m² as calculated in terms ofpolydimethylsiloxane. Alternatively, the said separator needs to meetthe requirements that the coated amount of silicone on the saidseparator be 0.1 g/m² or less, particularly preferably 0.07 g/m² or lessas calculated in terms of polydimethylsiloxane. When the amount ofsilicone attached to the cleaning layer or the coated amount of siliconeon the separator exceeds the aforementioned predetermined value, therearises a problem that the constituents of the release treatment incontact with the outermost surface of the cleaning layer or siliconewhich is one of the constituents moves to the surface of the cleaninglayer to contaminate the cleaning layer, causing secondary contaminationof the contact site in the substrate treatment device. The measurementof the amount of silicone can be carried out by measuring the surface ofa sample within a 30 mmφ measurement range for intensity of Si—Kα usinga fluorescent X-ray measuring instrument, and then subjecting themeasured value to calculation in terms of polydimethylsiloxane. Theconversion formula is represented by the following equation (1).y=0.00062x  (1)y: Amount of polydimethylsiloxane (g/m²)x: Intensity of Si—Kα (kcps)

The separator to be used in the present invention is not specificallylimited so far as the amount of silicone attached to the cleaning layeror the coated amount of silicone on the separator is not greater than apredetermined value as mentioned above. For example, the silicone resinto be used as a release treatment may be solvent type, emulsion type,solvent-free type or the like. Alternatively, a curing type siliconeresin such as condensation reaction curing type, addition reactioncuring type, ultraviolet-curing type and electron ray-curing typesilicone resins can be used. The silicone resin may further comprisevarious additives such as non-functional silicone as light strippingadditive or silicone resin as heavy stripping additive incorporatedtherein besides the main component such as polydimethylsiloxane.

The material to be used as separator is not specifically limited but maybe a plastic film made of polyvinyl chloride, vinyl chloride copolymer,polyethylene terephthalate, polybutylene terephthalate, polyurethane,ethylene acetate-vinyl copolymer, ionomer resin, ethylene-(meth)acrylicacid copolymer, ethylene-(meth)acrylic acid ester copolymer,polystyrene, polycarbonate or the like.

The second cleaning sheet of the present invention comprises a separatorhaving a thickness of normally from 25 μm to 100 μm made of apolyolefin-based resin as a protective film for protecting the surfaceof the cleaning layer. Examples of the polyolefin-based resin includepolyethylene, polypropylene, ethylene-ethyl acrylate copolymer, etc.This kind of a film such as polyether exhibits a low critical surfacetension even if it is not release-treated with a silicone or wax andthus can be predetermined to have a lowered peel adhesion with respectto the surface of the cleaning layer. Further, the film made of a softvinyl chloride is disadvantageous in that a large amount of aplasticizer incorporated in the film moves to the surface of thecleaning layer to cause contamination in the substrate treatment deviceor hydrogen chloride which has liberated from the polyvinyl chloridecauses contamination in the device. However, the polyolefin-based resincauses no such problems.

Such a cleaning layer surface protective film is prepared by normallyadding various additives to the aforementioned polyolefin-based resin,and then working the polyolefin-based resin into a film form by afilm-forming device such as extruder and calender. The present inventionis characterized in that the aforementioned additives are free of heatdeterioration inhibitor and lubricant or, if any, the sum of the amountof the two additives is restricted to a range as narrow as less than0.01 parts by weight based on 100 parts by weight of polyolefin-basedresin.

Examples of the heat deterioration inhibitor include phenolic heatdeterioration inhibitor, aromatic amine-based heat deteriorationinhibitor, organic sulfur-based heat deterioration inhibitor, organicphosphorus-based heat deterioration inhibitor, and metal compound-basedheat deterioration inhibitor. When the sum of the amount of the heatdeterioration inhibitor and lubricant is not smaller than 0.01 parts byweight based on 100 parts by weight of polyolefin-based resin, theseadditives move to the surface of the cleaning layer, making it difficultto certainly prevent contamination in the substrate treatment device.

Further, since the protective film made of the aforementionedpolyolefin-based resin must withstand the heating and drying step duringthe coating of the cleaning layer-forming adhesive, the polyolefin-basedresin which is a film-forming material preferably exhibits a heatdeformation temperature of 80° C. or higher (according to JIS K7207 at aload of 0.45 MPa). Such a protective film is not subjected to releasetreatment.

The cleaning layer is not specifically limited in its material, etc.However, a material which has cured by an activation energy source suchas ultraviolet rays and heat to have a three-dimensionally networkedmolecular structure that gives a lowered adhesion is preferably used.For example, the 180° peel adhesion with respect to silicon wafer(mirror surface) is 0.20 N/10 mm or less, preferably from about 0.010 to0.10 N/10 mm. When this adhesion exceeds 0.20 N/10 mm, the cleaninglayer adheres to the non-cleaning area in the device during conveyance,possibly causing conveyance troubles.

Further, in the present invention, the cleaning sheet can be cut into alabel form which is then used as a label sheet with cleaning function.In this case, the cutting method is not specifically limited. However,when the adhesive of the cleaning layer has not been polymerized andcured, it is disadvantageous in that the adhesive layer of the cleaninglayer protrudes from the cutting section of the sheet or is attached tothe cutting section or the adhesive ropes or is cut to uneven depth togive roughened cutting section, causing malcutting in the worst case.Further, when the polymerization curing reaction is effected after thecutting of the sheet, the adhesive exposed on the cutting section isprevented from being polymerized due to oxygen inhibition, occasionallycausing contamination of the substrate treatment device by the adhesive.Therefore, it is preferred that polymerization curing reaction bepreviously effected before cutting. To this end, it is preferred thatthe tensile modules of the cleaning layer be 10 MPa or more, preferablyfrom 10 to 2,000 Mpa (according to JIS K7127) to prevent the occurrenceof the aforementioned problems with sheet cutting. By predetermining thetensile modulus to such a specified value or more, the protrusion of theadhesive from the cleaning layer or malcutting during label cutting canbe prevented, making it possible to produce a label sheet with cleaningfunction causing no contamination by adhesive. When the tensile modulusexceeds 2,000 Mpa, the capacity of removing attached foreign mattersfrom the conveyance system is deteriorated. When the tensile modulus issmaller than this range, the aforementioned problems with cutting canoccur or the adhesive can adhere to the area to be cleaned in the deviceduring conveyance, possibly causing troubles in conveyance.

As a specific example of such a cleaning layer, a cleaning layercomprising a compound having one or more unsaturated double bonds permolecule incorporated in a pressure-sensitive adhesive polymer ispreferred.

Further, an examples of such a pressure-sensitive adhesive polymer is anacrylic polymer comprising as a monomer a (meth)acrylic acid and/or(meth)acrylic acid ester selected from the group consisting of acrylicacid, acrylic acid ester, methacrylic acid and methacrylic acid ester.By using a compound having two or more unsaturated double bonds permolecule as a copolymerizable monomer to synthesize this acrylic polymeror chemically bonding a compound having unsaturated double bonds permolecule to the acrylic polymer synthesized by a reaction betweenfunctional groups so that the acrylic polymer molecule comprisesunsaturated double bonds incorporated therein, the polymer itself, too,can be allowed to take part in the polymerization curing reaction whengiven an activation energy.

The compound having one or more unsaturated double bonds per molecule tobe used herein (hereinafter referred to as “polymerizable unsaturatedcompound”) is preferably a nonvolatile low molecular compound having aweight-average molecular weight of 10,000 or less. It is preferred thatthis compound have a molecular weight of 5,000 or less to undergoefficient three-dimensional networking of adhesive layer during curing.Examples of such a polymerizable compound include phenoxy polyethyleneglycol (meth)acrylate, ε-caprolactone (meth)acrylate, polyethyleneglycol di(meth)acrylate, polypropylene glycol di(meth)acrylate,trimethylolpropane tri(meth)acrylate, dipentaerythritolhexa(meth)acrylate, urethane (meth)acrylate, epoxy (meth)acrylate,oligoester (meth)acrylate, etc. Among these polymerizable compounds, oneor more compounds are used.

Further, the polymerization initiator to be incorporated in the adhesiveis not specifically limited. Any known material may be used as such apolymerization initiator. For example, if as an activation energy sourcethere is used heat, a heat polymerization initiator such as benzoylperoxide and azobisisobutyronitrile may be used. If light is used, aphotopolymerization initiator such as benzoyl, benzoin ethyl ether,dibenzyl, isopropyl benzoin ether, benzophenone, Michler's ketonechlorothioxanthone, dodecyl thioxanthone, dimethyl thioxanthone,acetophenone diethyl ketal, benzyl dimethyl ketal, α-hydroxy cyclohexylphenyl ketone, 2-hydroxymetyl phenyl propane and2,2-dimethoxy-2-phenylacetophenone may be used.

The thickness of the cleaning layer is not specifically limited but isnormally from about 5 to 100 μm.

The present invention also provides a cleaning sheet comprising anordinary adhesive layer provided on the other side of the cleaning layeror the other side of the backing. In this case, the adhesive layer onthe other side is not specifically limited in its material, etc. so faras it satisfies sticking function. An ordinary adhesive (e.g., acrylicadhesive, rubber-based adhesive) may be used. The thickness of theadhesive layer is normally from about 5 to 100 μm. In the case where aconveying member such as substrate is peeled off such an adhesive toreuse a conveying member such as substrate in the present invention, theadhesion of such an ordinary adhesive is preferably from about 0.21 to0.98 N/10 mm, particularly from about 0.40 to 0.98 N/10 mm as calculatedin terms of 180° peel adhesion with respect to silicon wafer (mirrorsurface) so that the substrate can be easily re-peeled without beingpeeled during conveyance after cleaning.

The separator to be used in the adhesive layer on the other is notspecifically limited. Examples of the separator include plastic filmmade of polyolefin such as polyethylene, polypropylene, polybutene,polybutadiene and polymethyl pentene, polyvinyl chloride, vinyl chloridecopolymer, polyethylene terephthalate, polybutylene terephthalate,polyurethane, ethylene-vinyl acetate copolymer, ionomer resin,ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid estercopolymer, polystyrene and polycarbonate which has been release-treatedwith a silicone-based releasing agent, long-chain alkyl-based releasingagent, fluorine-based releasing agent, aliphatic acid amide-basedreleasing agent, silica-based releasing agent or the like. The thicknessof the separator is normally from about 10 to 100 μm.

The backing for the cleaning layer is not specifically limited. Examplesof the backing include plastic film made of polyethylene, polyethyleneterephthalate, acetyl cellulose, polycarbonate, polypropylene,polyimide, polyamide, polycarbodiimide, nylon film, etc. The thicknessof the backing film is normally from about 10 μm to 100 μm.

In the third label sheet with cleaning function of the presentinvention, the separator of continuous length needs to have a 180° peeladhesion of 0.05 N/50 mm or more, preferably 0.1 N/50 mm or more,particularly from about 0.1 to 0.5 N/50 mm to peel itself off theordinary adhesive layer. Alternatively, the said separator needs to havea percent residual adhesion of 85% or more, preferably 90% or more,particularly from about 90 to 110% as measured by No. 31 B tape (tradename: polyester adhesive tape; substrate: polyester; adhesive: acryl)produced by NITTO DENKO CORPORATION. The measurement of the peeladhesion of the separator is carried out by determining the forcerequired to peel the separator off the cleaning label at an angle of180° and a rate of 300 mm/ml in an ordinary state (23° C., 50% RH) usinga tensile testing machine (specified in AS1635, FINAT-10, FS-147,PSTC-4). In some detail, a No. 31 B polyester adhesive tape produced byNITTO DENKO CORPORATION is stuck to a cold-rolled stainless steel plate(SUS304) specified in JIS G 4305. The peel adhesion is then measured atan angle of 180° in an ordinary state (23° C., 50% RH) as a basicadhesion (F₀). Subsequently, the aforementioned polyester adhesive tapeis stuck to the said separator using a 19.6 N (2 kg) roller. Thelaminate is then pressed at a load of 49 N (5 kg). After 24 hours, theadhesive tape is then peeled. The adhesive tape thus peeled is thenstuck to the aforementioned stainless steel plate. The peel adhesion isthen measured in the same manner as mentioned above to determineresidual adhesion (F). From the basic adhesion (F₀) and residualadhesion (F) thus obtained, percent residual adhesion is then determinedusing the following equation (1):Percent residual adhesion (%)=(F/F ₀)×100  (1)

If the 180° peel adhesion of the said separator is less Than thepredetermined value, the cleaning label is partly peeled off theseparator of continuous length after the production of the label sheetwith cleaning function, possibly causing the change of adhesion of theadhesive or the contamination of the adhesive by foreign matters. If the180° peel adhesion exceeds 0.5 N/50 mm, heavy-duty peeling occurs whenthe label is peeled off the separator, possibly deterioratingworkability. Further, if the percent residual adhesion is smaller thanthe predetermined value, the release layer components are transferred tothe adhesive during the storage of label sheet, possibly deterioratingthe adhesive properties of the label or making the peel adhesion of thelabel with respect to the separator in stable to disadvantage. It isalso disadvantageous in that when such a cleaning label is stuck to theconveying member, malsticking occurs due to contamination by foreignmatters or the age stability of the conveying member with cleaningfunction to which the cleaning label has been stuck deteriorates.

In the present invention, the separator of continuous length is notspecifically limited in its material so far as the peel adhesion thereofis not smaller than the predetermined value as mentioned above but maybe a plastic film made of polyolefin such as polyethylene,polypropylene, polybutene, polybutadiene and polymethyl pentene,polyvinyl chloride, vinyl chloride copolymer, polyethyleneterephthalate, polybutylene terephthalate, polyurethane, ethylene-vinylacetate copolymer, ionomer resin, ethylene-(meth)acrylic acid copolymer,ethylene-(meth)acrylic acid ester copolymer, polystyrene andpolycarbonate which has been release-treated with a silicone-basedreleasing agent, long-chain alkyl-based releasing agent, fluorine-basedreleasing agent, aliphatic acid amide-based releasing agent,silica-based releasing agent or the like.

The aforementioned cleaning layer exhibits a 180° peel adhesion of 0.20N/10 mm or less, preferably from about 0.01 to 0.1 N/10 mm with respectto silicon wafer (mirror surface) (measured according to JIS Z0237).When this adhesion exceeds 0.20 N/10 mm, the cleaning layer comes incontact with the area to be cleaned in the device during conveyance,possibly causing troubles in conveyance. The thickness of the cleaninglayer is not specifically limited but is normally from about 5 to 100μm. The release film to be used in the protection of the cleaning layeris not specifically limited but may be a plastic film made of polyolefinsuch as polyethylene, polypropylene, polybutene, polybutadiene andpolymethyl pentene, polyvinyl chloride, vinyl chloride copolymer,polyethylene terephthalate, polybutylene terephthalate, polyurethane,ethylene-vinyl acetate copolymer, ionomer resin, ethylene-(meth)acrylicacid copolymer, ethylene-(meth)acrylic acid ester copolymer, polystyreneand polycarbonate which has been release-treated with a silicone-basedreleasing agent, long-chain alkyl-based releasing agent, fluorine-basedreleasing agent, aliphatic acid amide-based releasing agent,silica-based releasing agent or the like.

For the preparation of the label sheet with cleaning function accordingto the present invention, a cleaning sheet comprising the aforementionedcleaning layer provided on one side of a backing and an ordinaryadhesive layer provided on the other side of the backing is used. Theadhesive layer on the other side is not specifically limited in itsmaterial, etc. so far as the separator of continuous length exhibits theabove defined value or more but may be made of an ordinary adhesive(e.g., acrylic adhesive, rubber-based adhesive). In this arrangement,the cleaning label can be peeled off the separator, stuck to conveyingmembers such as various with the ordinary adhesive layer, and thenconveyed through the device as a conveying member with cleaning functionso that it comes in contact with the site to be cleaned for cleaning.Since the reuse of the conveying member requires that the conveyingmember be peeled off the adhesive layer, the adhesion of the saidadhesive layer can be predetermined to a range of from 0.01 to 10.0 N/10mm, particularly from about 0.05 to 5.0 N/10 mm as calculated in termsof 180° peel adhesion with respect to silicon wafer (mirror surface) toeasily repeel the conveying member off the adhesive layer without beingpeeled during conveyance after cleaning.

The present invention will be further described in connection with thedrawings, but the present invention is not limited thereto.

FIG. 1 is a plan view illustrating an example of the label sheet withcleaning function of the present invention wherein a plurality ofcleaning labels A are continuously provided on a separator 1 ofcontinuous length apart from each other. As shown in FIG. 2 (sectionalview taken in the line a-a of FIG. 1), this label A comprises a cleaninglayer 3 and a release film 4 provided on one side of a backing 2 and anordinary adhesive layer 5 provided on the other side of the backing 2and is peelably provided on the separator 1 with this adhesive layer 5interposed therebetween.

In operation, the cleaning label is peeled off the separator 1, and thenstuck to a conveying member such as semiconductor wafer. The releasefilm 4 is then peeled off the cleaning layer 3. The label sheet can thenbe conveyed into a device to clean the site to be cleaned.

In the process for the production of the fourth label sheet withcleaning function of the present invention, it is required that thenumber of foreign matters having a size of 0.2 μm or more to betransferred from the cleaning layer of the label sheet thus obtained tothe silicon wafer be 20 per inch square or less, particularly 10 perinch square or less. If the transferred amount of foreign mattersexceeds 20 per inch square, a problem arises that the contact site inthe substrate treatment device can be contaminated.

In the present invention, the process for the production of the fourthlabel sheet is not specifically limited so far as the transferred amountof foreign matters is not greater than the predetermined value asmentioned above. In particular, however, a process is preferablyeffected which comprises peeling a first release film of the cleaninglayer before the polymerization curing reaction of the adhesive of saidcleaning layer, subjecting the cleaning layer to polymerization curingunder conditions that there are no substantial effect of oxygen,protecting the surface of said cleaning layer by a second release film,and then punching the sheet into a label form. If the adhesiveconstituting the cleaning sheet has not been polymerized and curedduring the sheet punching, it is disadvantageous in that the adhesivelayer of the cleaning layer protrudes from the punched section of thesheet or is attached to the punched section or the adhesive ropes or ispunched to uneven depth to give roughened punched section, causingmalpunching in the worst case. Further, when the polymerization curingreaction is effected after the punching of the sheet, the adhesiveexposed on the punched section is prevented from being polymerized dueto oxygen inhibition, occasionally causing contamination of thesubstrate treatment device by the adhesive.

In the present invention, it is preferred that the tensile modules ofthe cleaning layer be 10 MPa or more, preferably from 10 to 2,000 Mpa(according to JIS K7127) to prevent the occurrence of the aforementionedproblems with sheet punching. By predetermining the tensile modulus tosuch a specified value or more, the protrusion of the adhesive from thecleaning layer or malpunching during sheet punching can be prevented,making it possible to produce a label sheet with cleaning functioncausing no contamination by adhesive in the precutting process. When thetensile modulus is smaller than 10 MPa, the aforementioned problems withsheet punching can occur or the adhesive can adhere to the area to becleaned in the device during conveyance, possibly causing troubles inconveyance. On the contrary, when the tensile modulus is too great, thecapacity of removing attached foreign matters from the conveyance systemis deteriorated.

In the present invention, it is required that the cleaning layer befreed of the first release film before the polymerization curingreaction of the cleaning layer and then subjected to polymerization andcuring under conditions that there are no substantial effect of oxygen.When the cleaning layer is subjected to polymerization and curingwithout being freed of first release film, the constituents of thereleasing agent such as silicone which come in contact with theoutermost surface of the cleaning layer or part thereof move to thesurface of the cleaning layer, giving a cause of contamination from thecleaning layer. Further, the polymerization and curing of the cleaninglayer under conditions that there are no substantial effect of oxygencan be accomplished e.g., by irradiation with an activation energysource in vacuum atmosphere (pressure: about 133 Pa).

Further, the cleaning layer which has been subjected to polymerizationand curing is protected by a second release film on the surface thereof,and then subjected to sheet punching to make a label form. The first andsecond release films for protecting the surface of the cleaning layerare not specifically limited so far as they can be re-peeled off thecleaning layer during production or use of the cleaning sheet. However,the plastic film as separator described later or re-releasable adhesivesheet can be used. The first and second release films may be the same ordifferent. However, the production process of the present invention iseffective particularly when the first release film is a film withsilicone-based releasing agent as described in paragraph (0010).

In accordance with the process for the production of the label sheetwith cleaning function of the present invention, a cleaning sheetcomprising a cleaning layer made of the aforementioned specific adhesiveprovided on one side of a backing with the surface thereof protected bya release film wherein the other side of the backing is peelablyprovided on a separator with an ordinary adhesive layer interposedtherebetween is subjected to curing of curing adhesive as cleaninglayer, and then subjected to sheet punching on the portion other thanseparator to make a label form. In this case, the punching process andworked form are not specifically limited. However, the cleaning sheetmay be punched according to the shape of the conveying member describedlater, and then freed of unnecessary sheet to form a label.Alternatively, unnecessary sheet can be peeled off the portion otherthan label and reinforced portion with a part of the sheet left unpeeledas reinforced portion apart from the label around the label or at theend of the sheet to form a label.

In accordance with the process for the production of the label sheetwith cleaning function of the present invention, a cleaning sheetcomprising the aforementioned specific cleaning layer provided on oneside of a backing wherein the other side of the backing is peelablyprovided on a separator with an ordinary adhesive layer interposedtherebetween is used. The adhesive layer on the other side is notspecifically limited in its material, etc. so far as it satisfies theadhesive properties but may be an ordinary adhesive (e.g., acrylicadhesive, rubber-based adhesive). In this arrangement, the label withcleaning function can be peeled off the separator described later, stuckto conveying members such as various with the ordinary adhesive layer,and then conveyed through the device as a conveying member with cleaningfunction so that it comes in contact with the site to be cleaned forcleaning. In the case where the substrate is peeled off the adhesivelayer after cleaning to reuse the conveying member such as theaforementioned substrate, the adhesion of the ordinary adhesive layer isnot specifically limited. However, if the adhesion of the ordinaryadhesive layer is from 0.01 to 10 N/10 mm, particularly from about 0.1to 5 N/10 mm as calculated in terms of 180° peel adhesion with respectto silicon wafer (mirror surface), the substrate can be easily re-peeledoff the adhesive layer without being peeled during conveyance aftercleaning to particular advantage.

In accordance with the process for the production of the label sheetwith cleaning function of the present invention, a cleaning sheetcomprising a cleaning layer made of the aforementioned specific adhesiveprovided on one side of a backing with the surface thereof protected bya release film wherein the other side of the backing is peelablyprovided on a separator with an ordinary adhesive layer interposedtherebetween is subjected to curing of curing adhesive as cleaninglayer, and then subjected to sheet punching on the portion other thanseparator to make a label form. In this case, the punching process andworked form are not specifically limited. However, the cleaning sheetmay be punched according to the shape of the conveying member describedlater, and then freed of unnecessary sheet to form a label.Alternatively, unnecessary sheet can be peeled off the portion otherthan label and reinforced portion with a part of the sheet left unpeeledas reinforced portion apart from the label around the label or at theend of the sheet to form a label.

In accordance with the process for the production of the label sheetwith cleaning function of the present invention, a cleaning sheetcomprising the aforementioned specific cleaning layer provided on oneside of a backing wherein the other side of the backing is peelablyprovided on a separator with an ordinary adhesive layer interposedtherebetween is used. The adhesive layer on the other side is notspecifically limited in its material, etc. so far as it satisfies theadhesive properties but may be an ordinary adhesive (e.g., acrylicadhesive, rubber-based adhesive). In this arrangement, the label withcleaning function can be peeled off the separator described later, stuckto conveying members such as various with the ordinary adhesive layer,and then conveyed through the device as a conveying member with cleaningfunction so that it comes in contact with the site to be cleaned forcleaning. In the case where the substrate is peeled off the adhesivelayer after cleaning to reuse the conveying member such as theaforementioned substrate, the adhesion of the ordinary adhesive layer isnot specifically limited. However, if the adhesion of the ordinaryadhesive layer is from 0.01 to 10 N/10 mm, particularly from about 0.1to 5 N/10 mm as calculated in terms of 180° peel adhesion with respectto silicon wafer (mirror surface), the substrate can be easily re-peeledoff the adhesive layer without being peeled during conveyance aftercleaning to particular advantage.

The separator in the present invention is not specifically limited sofar as the cleaning label can be peeled off the separator but may be aplastic film made of polyolefin such as polyethylene, polypropylene,polybutene, polybutadiene and polymethyl pentene, polyvinyl chloride,vinyl chloride copolymer, polyethylene terephthalate, polybutyleneterephthalate, polyurethane, ethylene-vinyl acetate copolymer, ionomerresin, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylicacid ester copolymer, polystyrene and polycarbonate which has beenrelease-treated with a silicone-based releasing agent, long-chainalkyl-based releasing agent, fluorine-based releasing agent, aliphaticacid amide-based releasing agent, silica-based releasing agent or thelike. The thickness of the separator is not specifically limited but isnormally from about 10 to 100 μm.

The shape of the label A is not specifically limited and may becircular, wafer-shaped, flame-shaped, shape having protrusions for chuckportion, etc. or the like depending on the shape of the conveying membersuch as substrate to which the label A is stuck.

The conveying member to which the cleaning sheet or cleaning label isstuck is not specifically limited but may be a flat panel displaysubstrate such as semiconductor wafer, LCD and PDP, substrate such ascompact disc and MR head or the like.

EXAMPLES

The present invention will be described in the following examples, butthe present invention is not limited thereto. The term “parts” as usedhereinafter is meant to indicate “parts by weight”.

Example 1-1

100 parts of an acryl polymer (weight-average molecular weight: 700,000)obtained from a monomer mixture consisting of 75 parts of 2-ethylhexylacrylate, 20 parts of methyl acrylate and 5 parts of acrylic acid wereuniformly mixed with 150 parts of a polyfunctional urethane acrylate(trade name: UV-1700B, produced by Nippon Synthetic Chemical IndustryCo., Ltd.), 3 parts of a polyisocyanate compound (trade name: Colonate,produced by Nippon Polyurethane Industry Co., Ltd.) and 10 parts ofbenzyl dimethyl ketal (trade name: Irgacure 651, produced by CibaSpecialty Chemicals Co., Ltd.) as a photopolymerization initiator toprepare an ultraviolet-curing adhesive solution.

Separately, an adhesive solution obtained in the same manner asmentioned above except that the aforementioned adhesive was free ofbenzyl dimethyl ketanol was applied to one side of a polyester backingfilm having a width of 250 mm and a thickness of 25 μm to a drythickness of 10 μm to provide an ordinary adhesive layer thereon. To thesurface of the ordinary adhesive layer was then stuck a polyester-basedrelease film having a thickness of 38 μm which had been release-treatedwith a silicone-based releasing agent. Subsequently, the previouslymentioned ultraviolet-curing adhesive solution was applied to the otherside of the backing film to a dry thickness of 15 μm to provide anadhesive layer as a cleaning layer. To the surface of the adhesive layerwas then stuck a protective film which had been release-treated with asilicone-based releasing agent as a separator A.

This sheet was then irradiated with an ultraviolet ray having a centralwavelength of 365 nm at an integrated dose of 1,000 mJ/cm².

The separator A, which is a protective film for the cleaning layer, wasthen peeled off the cleaning sheet A. The amount of silicone attached tothe surface of the cleaning layer was then measured. For measurement, afluorescent X-ray measuring instrument produced by Rigaku Corporationwas used. The surface of the cleaning layer was measured for intensityof Si—Kα in an area of 30 mmφ. The measured value was then subjected tocalculation in terms of polydimethylsiloxane. As a result, the intensityof Si—Kα was 4.2 kcps, which is 0.003 g/m² as calculated in terms ofpolydimethylsiloxane. Further, the separator A was measured for coatedamount of silicone in an area of 30 mm by the fluorescent X-raymeasuring instrument. As a result, the intensity of Si—Kα was 104 kcps,which is 0.064 g/m² as calculated in terms of polydimethylsiloxane.

The tensile modulus of the adhesive layer of this cleaning sheet A afterultraviolet curing was 55 MPa. The tensile modulus was measuredaccording to JIS K7127 testing method.

Further, the adhesive layer on the cleaning layer side was stuck to themirror surface of a silicon wafer over a width of 10 mm, and thenmeasured for 180° peel adhesion with respect to the silicon wafer(mirror surface) of the ordinary adhesive layer on the cleaning layerside according to JIS Z0237. As a result, it was 0.008 N/10 mm.

Moreover, 180° peel adhesion with respect to the silicon wafer (mirrorsurface) of the ordinary adhesive layer on the other side was measuredin the same manner as mentioned above. As a result, it was 0.85 N/10 mm.

The release film on the ordinary adhesive layer side of this cleaningsheet A was peeled. The cleaning sheet A was then stuck to the back side(mirror surface) of a 8 inch silicon wafer to prepare a conveyingcleaning wafer A with cleaning function.

Example 1-2

A cleaning sheet B was prepared in the same manner as in Example 1-1except that as the separator for protective film of the cleaning layerthere was used a separator B release-treated with a silicone-basedreleasing agent.

The separator B, which is a protective film for the cleaning layer, wasthen peeled off the cleaning sheet B. The amount of silicone attached tothe surface of the cleaning layer was then measured. For measurement,the intensity of Si—Kα was measured in the same manner as in Example1-1. The measured value was then subjected to calculation in terms ofpolydimethylsiloxane. As a result, the intensity of Si—Kα was 0.6 kcps,which is less than 0.001 g/m² as calculated in terms ofpolydimethylsiloxane. Further, the separator B was measured for coatedamount of silicone in the same manner as mentioned above. As a result,the intensity of Si—Kα was 69 kcps, which is 0.042 g/m² as calculated interms of polydimethylsiloxane.

Further, a conveying cleaning wafer B with cleaning function wasprepared in the same manner as in Example 1-1.

Comparative Example 1-1

A cleaning sheet C was prepared in the same manner as in Example 1-1except that as the separator for protective film of the cleaning layerthere was used a separator C release-treated with a silicone-basedreleasing agent.

The separator C, which is a protective film for the cleaning layer, wasthen peeled off the cleaning sheet C. The amount of silicone attached tothe surface of the cleaning layer was then measured. For measurement,the intensity of Si—Kα was measured in the same manner as in Example1-1. The measured value was then subjected to calculation in terms ofpolydimethylsiloxane. As a result, the intensity of Si—Kα was 9.8 kcps,which is less than 0.006 g/m² as calculated in terms ofpolydimethylsiloxane. Further, the separator C was measured for coatedamount of silicone in the same manner as mentioned above. As a result,the intensity of Si—Kα was 214 kcps, which is 0.13 g/m² as calculated interms of polydimethylsiloxane.

Further, a conveying cleaning wafer C with cleaning function wasprepared in the same manner as in Example 1-1.

The aforementioned cleaning sheets A to C of Examples 1-1 and 1-2 andComparative Example 1-1 were then subjected to contamination test onsemiconductor wafer and foreign matter removal test in substratetreatment device by conveying cleaning wafers A to C with cleaningfunction in the following manner. The results are as set forth in Table1-1.

<Evaluation of Wafer Contamination>

The cleaning layer of the cleaning sheet was stuck to the entire mirrorsurface of the 8 inch silicon wafer by a hand roller while the separator(protective film) was being peeled. Thereafter, the cleaning sheet waspeeled off the wafer. The foreign matters having a size of 0.2 μm ormore attached to the mirror surface were counted by a laser surfaceinspection device.

<Foreign Matter Removal Test>

Using a laser surface inspection device, foreign matters having a sizeof 0.2 μm or more on the mirror surface of three sheets of brand-new 8inch silicon wafer were measured. The results were 4, 5 and 2,respectively. These wafers were then conveyed into separate substratetreatment devices with an electrostatic attraction mechanism with itsmirror surface facing downward. The mirror surface of these wafers werethen measured by the laser surface inspection device. The results were33,643, 35,773 and 31,032, respectively, in an area of the 8 inch wafersize.

Subsequently, the protective film on the cleaning layer side was peeledoff the conveying cleaning wafers A to C thus obtained. These waferswere then conveyed over the aforementioned substrate treatment devicehaving the wafer stage to which the foreign matters had been attached.As a result, these wafers could be conveyed without any troubles.Thereafter, a brand-new 8 inch silicon wafer was conveyed with itsmirror surface facing downward, and then measured for the occurrence offoreign matters having a size of 0.2 μm or more by a laser foreignmatter inspection device. This operation was effected five times.

TABLE 1-1 Comparative Example 1-1 Example 1-2 Example 1-1 Amount ofsilicone 0.003 Less than 0.006 attached to cleaning 0.001 layer (g/m²)Coated amount of 0.064 0.042 0.133 silicone on separator (g/m²) Numberof foreign 31 2 443 matters (pieces/8 inch) Percent removal of 85 96 51foreign matters (%/after 5 times of operation)

As can be seen in the aforementioned results, the cleaning sheets ofExamples 1-1 and 1-2 comprising as a separator (protective film) forcleaning layer a protective film release-treated with a silicone-basedreleasing agent wherein the amount of silicone attached to said cleaninglayer when said separator is peeled off said cleaning layer is 0.005g/m² or less as calculated in terms of polydimethylsiloxane or thecoated amount of silicone on said separator is 0.1 g/m² or less ascalculated in terms of polydimethylsiloxane could prevent theconstituents of the silicone-based releasing agent or part thereof frommoving to the surface of the cleaning layer. As a result, it was foundthat the use of these cleaning wafers makes it possible to drasticallyeliminate contamination on the substrate treatment device, giving a highcapacity of removing foreign matters. On the contrary, it was found thatthe cleaning sheet of Comparative Example 1-1, which falls outside thescope of the present invention, shows a great amount of siliconeattached to silicon wafer and, as a result, the use of these cleaningwafers causes back contamination of the device, deteriorating thecapacity of removing foreign matters and hence disabling the usethereof.

Example 2-1

100 parts of a low density polyethylene resin produced by ASAHI CHEMICALINDUSTRY CO., LTD. were extruded free of heat deterioration inhibitorand lubricant through a flat film-producing machine [produced by SHIModern Machinery, Ltd.] at an extrusion temperature of 200° C. and atake-off speed of 4 m/min to form a film. Thus, a cleaning layer surfaceprotective film A having a thickness of 100 μm was obtained.

100 parts of an acryl polymer (weight-average molecular weight: 700,000)obtained from a monomer mixture of 75 parts of 2-ethylhexyl acrylate, 20parts of methyl acrylate and 5 parts of acrylic acid were uniformlymixed with 50 parts of a polyethylene glycol 200 dimethacrylate (tradename: Nk Ester 4G, produced by Shinnakamura Kagaku K.K.), 50 parts ofurethane acrylate (trade name: U-N-01, produced by Shinnakamura KagakuK.K.), 3 parts of a polyisocyanate compound (trade name: Colonate L,produced by Nippon Polyurethane Industry Co., Ltd.) and 3 parts ofbenzyl dimethyl ketal (trade name: Irgacure 651, produced by CibaSpecialty Chemicals Co., Ltd.) as a photopolymerization initiator toprepare an ultraviolet-curing adhesive solution. Separately, an adhesivesolution obtained in the same manner as mentioned above except that theaforementioned adhesive was free of benzyl dimethyl ketanol was appliedto one side of a polyester backing film having a width of 250 mm and athickness of 25 μm to a dry thickness of 10 μm to provide an ordinaryadhesive layer thereon. To the surface of the ordinary adhesive layerwas then stuck a polyester-based release film having a thickness of 38μm. Subsequently, the previously mentioned ultraviolet-curing adhesivesolution was applied to the other side of the backing film to a drythickness of 40 μm to provide an adhesive layer as a cleaning layer. Tothe surface of the adhesive layer was then stuck the protective film Aprepared above.

This sheet was then irradiated with an ultraviolet ray having a centralwavelength of 365 nm at an integrated dose of 2,000 mJ/cm² to obtain acleaning sheet A of the present invention. The tensile modulus of theadhesive layer of the cleaning layer of this cleaning sheet A afterultraviolet curing was 55 MPa.

Tensile modulus was measured herein according to JIS K7127 testingmethod.

Further, the adhesive layer on the cleaning layer side was stuck to themirror surface of a silicon wafer over a width of 10 mm, and thenmeasured for 180° peel adhesion with respect to the silicon wafer(mirror surface) of the ordinary adhesive layer on the cleaning layerside according to JIS Z0237. As a result, it was 0.029 N/10 mm.

Moreover, 180° peel adhesion with respect to the silicon wafer (mirrorsurface) of the ordinary adhesive layer on the other side was measuredin the same manner as mentioned above. As a result, it was 0.10 N/10 mm.

The release film on the ordinary adhesive layer side of this cleaningsheet A was peeled. The cleaning sheet A was then stuck to the back side(mirror surface) of a 8 inch silicon wafer to prepare a conveyingcleaning wafer A with cleaning function.

Example 2-2

To 100 parts of a low density polyethylene resin produced by ASAHICHEMICAL INDUSTRY CO., LTD. were added 0.009 parts of an aliphatic acidester-based lubricant. The mixture was then subjected to film forming inthe same manner as in Example 1 to obtain a cleaning layer protectivefilm B. A cleaning sheet B and a conveying cleaning wafer B withcleaning function were prepared in the same manner as in Example 2-1except that the cleaning layer surface protective film B was used as aseparator for cleaning layer.

Comparative Example 2-1

To 100 parts of a low density polyethylene resin produced by ASAHICHEMICAL INDUSTRY CO., LTD. were added 0.01 parts of a phenolic heatdeterioration inhibitor and 0.01 parts of an aliphatic acid ester-basedlubricant. The mixture was then subjected to film forming in the samemanner as in Example 2-1 to obtain a cleaning layer protective film C. Acleaning sheet C and a conveying cleaning wafer C with cleaning functionwere prepared in the same manner as in Example 2-1 except that thecleaning layer surface protective film C was used as a separator forcleaning layer.

Comparative Example 2-2

To 100 parts of a low density polyethylene resin produced by ASAHICHEMICAL INDUSTRY CO., LTD. were added 0.1 parts of a phenolic heatdeterioration inhibitor and 0.1 parts of an aliphatic acid ester-basedlubricant. The mixture was then subjected to film forming in the samemanner as in Example 2-1 to obtain a cleaning layer protective film D. Acleaning sheet D and a conveying cleaning wafer D with cleaning functionwere prepared in the same manner as in Example 2-1 except that thecleaning layer surface protective film D was used as a separator forcleaning layer.

Comparative Example 2-3

A silicone-treated polyester film having a thickness of 50 μm was usedas a cleaning layer surface protective film E. A cleaning sheet E and aconveying cleaning wafer E with cleaning function were prepared in thesame manner as in Example 2-1 except that the cleaning layer surfaceprotective film E was used as a separator for cleaning layer.

The aforementioned cleaning sheets A to E of Examples 2-1 and 2-2 andComparative Examples 2-1 to 2-3 were then examined for peel adhesionrequired to peel the separator (cleaning layer surface protective film)off the cleaning layer. Further, these cleaning sheets A to E weresubjected to contamination test on semiconductor wafer and foreignmatter removal test in substrate treatment device by conveying cleaningwafers A to E with cleaning function in the following manner. Theresults are as set forth in Table 2-1.

<Evaluation of Wafer Contamination>

The cleaning layer of the cleaning sheet was stuck to the entire mirrorsurface of the 8 inch silicon wafer by a hand roller while the separator(protective film) was being peeled. Thereafter, the cleaning sheet waspeeled off the wafer. The foreign matters having a size of 0.2 μm ormore attached to the mirror surface were counted by a laser surfaceinspection device.

<Foreign Matter Removal Test>

Using a laser surface inspection device, foreign matters having a sizeof 0.2 μm or more on the mirror surface of five sheets of brand-new 8inch silicon wafer were measured. The results were 10, 8, 3, 5, and 11,respectively. These wafers were then conveyed into separate substratetreatment devices with an electrostatic attraction mechanism with itsmirror surface facing downward. The mirror surface of these wafers werethen measured by the laser surface inspection device. The results were33,156, 38,945, 32,144, 37,998, and 31,327, respectively, in an area ofthe 8 inch wafer size.

Subsequently, the protective film on the cleaning side was peeled offthe conveying cleaning wafers A to E thus obtained. These wafers werethen conveyed over the aforementioned substrate treatment device havingthe wafer stage to which the foreign matters had been attached. As aresult, these wafers could be conveyed without any troubles. Thereafter,a brand-new 8 inch silicon wafer was conveyed with its mirror surfacefacing downward, and then measured for the occurrence of foreign mattershaving a size of 0.2 μm or more by a laser foreign matter inspectiondevice. This operation was effected five times.

TABLE 2-1 Percent removal of Number of foreign foreign matters Peeladhesion matters on (%/after fives of separator wafer times of (N/50 mmwidth) (pieces/8 inch) operation) Example 2-1 0.2 3 96 Example 2-2 0.1511 90 Comparative 0.15 225 76 Example 2-1 Comparative 0.12 2,573 55Example 2-2 Comparative 0.03 9,816 32 Example 2-3

As can be seen in the aforementioned results, the cleaning sheets ofExamples 2-1 and 2-2 comprising as a separator (protective film) of thecleaning layer a cleaning layer protective film wherein the sum of theamount of heat deterioration inhibitor and lubricant is less than 0.01parts based on 100 parts of polyethylene-based resin showed a peeladhesion as small as 0.5 N/50 mm width or less with respect to thesurface of the cleaning layer and the separator could be easily peeledoff the cleaning layer without any defects such as partial falling ofthe cleaning layer composition. It was further shown that since thenumber of foreign matters attached to the silicon wafer was small, theuse of these cleaning wafers makes it possible to drastically eliminatecontamination on the substrate treatment device, giving a high capacityof removing foreign matters. On the contrary, it was found that thecleaning sheets of Comparative Examples 2-1 and 2-2, which fall outsidethe scope of the present invention in respect to the above mentioned sumof the amount of the two components, and the cleaning sheet ofComparative Example 2-3, which comprise a conventional silicone-treatedpolyester film, showed a great amount of foreign matters attached tosilicon wafer and, as a result, the use of these cleaning wafers causesback contamination in the device, deteriorating the capacity of removingforeign matters and hence disabling the use thereof.

Example 1-1

100 parts of an acryl polymer (weight-average molecular weight: 700,000)obtained from a monomer mixture consisting of 75 parts of 2-ethylhexylacrylate, 20 parts of methyl acrylate and 5 parts of acrylic acid wereuniformly mixed with 50 parts of a polyethylene glycol 200dimethacrylate (trade name: NK Ester 4G, produced by Shinnakamura KagakuK.K.), 50 parts of urethane acrylate (trade name: U-N-01, produced byShinnakamura Kagaku K.K.), 3 parts of a polyisocyanate compound (tradename: Colonate L, produced by Nippon Polyurethane Industry Co., Ltd.)and 3 parts of benzyl dimethyl ketal (trade name: Irgacure 651, producedby Ciba Specialty Chemicals Co., Ltd.) as a photopolymerizationinitiator to prepare an ultraviolet-curing adhesive solution A.

Separately, into a 500 ml three-necked flask type reaction vesselequipped with thermometer, agitator, nitrogen intake pipe and condenserwere charged 3 parts of 2-ethylhexyl acrylate, 10 parts of n-butylacrylate, and 15 parts of N,N-dimethylacrylamide, and 0.15 parts of2,2′-azobisisobutyronitrile and 100 parts of ethyl acetate aspolymerization initiators to make 200 g. The reaction mixture was thenstirred while nitrogen gas was being introduced thereinto for about 1hour to replace the air within by nitrogen. Thereafter, the internaltemperature of the reaction vessel was raised to 58° C. where thereaction mixture was then kept for about 4 hours to causepolymerization. As a result, an adhesive polymer solution was obtained.100 parts of the adhesive polymer solution were then uniformly mixedwith 3 parts of a polyisocyanate compound (trade name: Colonate L,produced by Nippon Polyurethane Industry Co., Ltd.) to obtain anadhesive solution A.

The aforementioned adhesive solution A was applied to therelease-treated surface of the separator A made of a polyester film ofcontinuous length (thickness: 38 μm; width: 250 mm) one side of whichhad been treated with a silicone-based releasing agent to a drythickness of 15 μm. On the adhesive layer was then laminated a polyesterfilm of continuous length (thickness: 25 μm; width: 250 mm). Theultraviolet-curing adhesive solution A was then applied to the film to adry thickness of 40 μm to provide an adhesive layer as a cleaning layer.To the surface of the adhesive layer was then stuck the release-treatedsurface of the same release film as mentioned above to obtain a sheet.

This sheet was then irradiated with an ultraviolet ray having a centralwavelength of 365 nm at an integrated dose of 1,000 mJ/cm² to obtain acleaning sheet A having an ultraviolet-cured cleaning layer.

The adhesive film which is a laminated material other than the separatoron the adhesive layer side of this cleaning sheet A was then punched inthe form of circle having a diameter of 200 mm. The unnecessary adhesivefilm was then continuously peeled and removed to prepare a label sheet Awith cleaning function of the present invention as shown in FIG. 1. Thepunching of this label sheet A with cleaning function was conductedwithout any problems of roping of adhesive or chipping. Afterpreparation, the label sheet A with cleaning function was observed. As aresult, no peeling of the cleaning label off the separator occurred, andthe cleaning label was retained on the separator. Further, there wereobserved neither protrusion of the ordinary adhesive from the end of thelabel nor contamination of the label by the adhesive. Further, the labelsheet A was stored for 1 month. However, no peeling of the label off theseparator occurred, demonstrating that the cleaning sheet A exhibits ahigh age stability.

This label sheet A with cleaning function was measured for 180° peeladhesion required to peel the separator off the cleaning label. It was0.1 N/50 mm. The measurement of the peel adhesion of the separator wascarried out by determining the force required to peel the separator offthe cleaning label at an angle of 180° and a rate of 300 mm/min in anordinary state (23° C., 50% RH) using a tensile testing machine(specified in AS1635, FINAT-10, FS-147, PSTC-4).

Further, percent residual adhesion was measured using a No. 31 B tape(polyester adhesive tape) produced by NITTO DENKO CORPORATION. In somedetail, a No. 31 B tape was stuck to a stainless steel plate (SUS304)specified in JIS G 4305. The peel adhesion (basic adhesion) was thenmeasured. The basic adhesion was 5.2 N/20 mm. Subsequently, theseparator A was stuck to the adhesive surface of the No. 31B tape usinga 19.6 N (2 kg) roller. The laminate was then pressed at a load of 49 N(5 kg). After 24 hours, the adhesive tape was then peeled. The adhesivetape thus peeled was then stuck to the aforementioned stainless steelplate. The peel adhesion was then measured in the same manner asmentioned above to determine residual adhesion. The residual adhesionwas 5.4 N/20 mm and the percent residual adhesion was 104%.

This ultraviolet-curing adhesive A was measured for tensile modulus (JISK7127 testing method). As a result, it was 49 Mpa after irradiated withan ultraviolet ray having a central wavelength of 365 nm at anintegrated dose of 1,000 mJ/cm².

The 180° peel adhesion of this ordinary adhesive layer with respect tosilicon wafer (mirror surface) was 0.25 N/10 mm.

This label sheet A with cleaning function was stuck to a 8 inch siliconwafer using a label sticker (NEL-GR3000, produced by NITTO SEIKI INC.)to prepare a conveying member A with cleaning function. At this time,the cleaning label was stuck to the mirror surface of the 8 inch siliconwafer. This operation was continuously effected over 25 sheets. As aresult, the sheet was stuck to the wafer without any problems. Thus, aconveying member A with cleaning function for conveyance with cleaningfunction was prepared.

Separately, using a laser surface inspection device, foreign mattershaving a size of 0.2 μm or more on the mirror surface of four sheets ofbrand-new 8 inch silicon wafer were measured. The first sheet showed 5pieces of foreign maters, the second sheet showed 3 pieces of foreignmaters, and the third sheet showed 5 pieces of foreign maters. Thesewafers were then conveyed into separate substrate treatment devices withan electrostatic attraction mechanism with its mirror surface facingdownward. The mirror surface of these wafers were then measured forforeign matters having a size of 0.2 or more by the laser surfaceinspection device. The first, second and third sheets showed 29,845,32,194 and 30,036 pieces of foreign matters, respectively, in an area ofthe 8 inch wafer size.

Subsequently, the release film on the cleaning side was peeled off theconveying member A with cleaning function for conveyance thus obtained.The conveying member A was then conveyed over the aforementionedsubstrate treatment device having the wafer stage to which 29,845 piecesof foreign matters had been attached. As a result, the conveying membercould be conveyed without any troubles. Thereafter, a brand-new 8 inchsilicon wafer was conveyed with its mirror surface facing downward, andthen measured for the occurrence of foreign matters having a size of 0.2μm or more by a laser foreign matter inspection device. This operationwas effected five times. The results are set forth in Table 3-1.

Example 3-2

A label sheet B with cleaning function was prepared in the same manneras in Example 3-1 except that as the separator of continuous length forlabel sheet with cleaning function there was a polyolefin film B(thickness: 70 μm; width: 250 mm) made of a low density polyethylene.The punching of this label sheet B with cleaning function was conductedwithout any problems of roping of adhesive or chipping. Afterpreparation, the label sheet B with cleaning function was observed. As aresult, no peeling of the cleaning label off the separator occurred, andthe cleaning label was retained on the separator. Further, there wereobserved neither protrusion of the ordinary adhesive from the end of thelabel nor contamination of the label by the adhesive. Further, the labelsheet B was stored for 1 month. However, no peeling of the label off theseparator occurred, demonstrating that the cleaning sheet B exhibits ahigh age stability.

This label sheet B with cleaning function was measured for 180° peeladhesion required to peel the separator off the cleaning label. It was0.15 N/50 mm.

Further, the separator B was measured for residual adhesion by No. 31Btape. The residual adhesion was 4.7 N/20 mm and the percent residualadhesion was 90%.

This label sheet B with cleaning function was stuck to a 8 inch siliconwafer using a label sticker (NEL-GR3000, produced by NITTO SEIKI INC.)to prepare a conveying member B with cleaning function. At this time,the cleaning label was stuck to the mirror surface of the 8 inch siliconwafer. This operation was continuously effected over 25 sheets. As aresult, the sheet was stuck to the wafer without any problems. Thus, aconveying member B with cleaning function for conveyance with cleaningfunction was prepared.

Subsequently, the release film on the cleaning side was peeled off theconveying member A with cleaning function for conveyance obtainedpreviously. The conveying member A was then conveyed over theaforementioned substrate treatment device having the wafer stage towhich 32,194 pieces of foreign matters had been attached. As a result,the conveying member could be conveyed without any troubles. Thereafter,a brand-new 8 inch silicon wafer was conveyed with its mirror surfacefacing downward, and then measured for the occurrence of foreign mattershaving a size of 0.2 μm or more by a laser foreign matter inspectiondevice. This operation was effected five times. The results are setforth in Table 3-1.

Comparative Example 3-1

A label sheet C with cleaning function was prepared in the same mannerwas in Example 3-1 except that as the separator of continuous length forlabel sheet with cleaning function there was a polyester film C(thickness: 38 μm; width: 250 mm). The punching of this label sheet Cwith cleaning function was Conducted without any problems of roping ofadhesive or chipping.

However, when the label sheet C with cleaning function was observedafter preparation, almost all the cleaning labels were observed to havebeen peeled off the separator, demonstrating that the label sheet wasnot prepared.

This label sheet C with cleaning function was measured for 180° peeladhesion required to peel the separator off the cleaning label. As aresult, the dispersion of peel adhesion was great among the labels to bemeasured. The 180° peel adhesion was 0.03 N/50 mm at maximum.

Further, the separator B was measured for residual adhesion by No. 31Btape. The residual adhesion was 4.0 N/20 mm and the percent residualadhesion was 77%.

This label sheet C with cleaning function was stuck to a 8 inch siliconwafer using a label sticker (NEL-GR3000, produced by NITTO SEIKI INC.)to prepare a conveying member C with cleaning function. At this time,the cleaning label was stuck to the mirror surface of the 8 inch siliconwafer. This operation was continuously effected over 25 sheets. As aresult, the cleaning label was completely peeled off the separator bythe sticker, causing frequent malsticking to wafer. Even the conveyingmember C with cleaning function which could be stuck to wafer had airbubbles (float) mixed therein during sticking, making it impossible toobtain a single good product. Accordingly, cleaning of the interior ofthe substrate treatment device by the conveying member C with cleaningfunction was suspended.

TABLE 3-1 Percent removal of foreign matters 1 sheet 2 sheets 3 sheets 4sheets 5 sheets conveyed conveyed conveyed conveyed conveyed Example 3-183% 88% 90% 92% 92% Example 3-2 80% 85% 90% 92% 92% Comparative Cleaningsuspended Example 3-1

Example 4-1

100 parts of an acryl polymer (weight-average molecular weight: 700,000)obtained from a monomer mixture consisting of 75 parts of 2-ethylhexylacrylate, 20 parts of methyl acrylate and 5 parts of acrylic acid wereuniformly mixed with 50 parts of a polyethylene glycol 200dimethacrylate (trade name: NK Ester 4G, produced by Shinnakamura KagakuK.K.), 50 parts of urethane acrylate (trade name: U-N-01, produced byShinnakamura Kagaku K.K.), 3 parts of a polyisocyanate compound (tradename: Colonate L, produced by Nippon Polyurethane Industry Co., Ltd.)and 3 parts of benzyl dimethyl ketal (trade name: Irgacure 651, producedby Ciba Specialty Chemicals Co., Ltd.) as a photopolymerizationinitiator to prepare an ultraviolet-curing adhesive solution.

Separately, an ordinary adhesive solution was obtained in the samemanner as mentioned above except that the aforementioned adhesive wasfree of benzyl dimethyl ketal.

The aforementioned adhesive solution was applied to the release-treatedsurface of the separator made of a polyester film of continuous length(thickness: 38 μm; width: 250 mm) one side of which had been treatedwith a silicone-based releasing agent to a dry thickness of 10 μm. Onthe adhesive layer was then laminated a polyester film of continuouslength (thickness: 25 μm; width: 250 mm). The ultraviolet-curingadhesive solution was then applied to the film to a dry thickness of 40μm to provide an adhesive layer as a cleaning layer. After drying, tothe surface of the adhesive layer was then stuck the release-treatedsurface of a first release film made of polyester film of continuouslength (thickness: 38 μm; width: 250 mm) one side of which had beentreated with a silicone-based releasing agent to obtain a sheet.

The first release film on the cleaning layer of this sheet was peeled.The sheet was then irradiated with an ultraviolet ray having a centralwavelength of 365 nm at an integrated dose of 1,000 mJ/cm² in a vacuumatmosphere (133 Pa). To the surface of the cleaning layer was then stucka polyolefin film (untreated) having a thickness of 50 μm as a secondrelease film to obtain a cleaning sheet having an ultraviolet-curedcleaning layer.

The adhesive film which is a laminated material other than the separatorof this cleaning sheet was then punched in the form of circle having adiameter of 200 mm. The unnecessary adhesive film was then continuouslypeeled and removed to prepare a cleaning label sheet of the presentinvention as shown in FIG. 1. The punching of this cleaning sheet wasconducted without any problems of roping of adhesive or chipping. Afterpreparation, the label sheet was observed. As a result, there wereobserved neither protrusion of the ordinary adhesive from the end of thelabel nor contamination of the label by the adhesive.

Further, the tensile modulus of the cleaning layer of this cleaningsheet after curing, i.e., during sheet punching was 49 MPa. The tensilemodulus was measured herein according to JIS K7127 testing method.

Moreover, the second release film on the cleaning layer of this cleaninglabel sheet was peeled. The cleaning label sheet was then stuck to a 8inch silicon wafer in such an arrangement that the cleaning layer camein contact with the wafer. The label sheet was then peeled off thewafer. The surface of the 8 inch silicon wafer was measured y a lasertype foreign matter measuring instrument. As a result, the number offoreign matters having a size of 0.2 μm or more was 14.

The cleaning label was peeled off the separator of the label sheet withcleaning function thus obtained, and then stuck to the back surface(mirror surface) of a 8 inch silicon wafer by a hand roller to prepare aconveying cleaning wafer with cleaning function. The 180° peel adhesionof the ordinary adhesive layer with respect to silicon wafer (mirrorsurface) was 2.5 N/10 mm.

Using this label sheet with cleaning function, the label was stuck tothe back surface (mirror surface) of a 8 inch silicon wafer by a labeltape sticker (trade name: NEL-GR3000, produced by NITTO SEIKI INC.).This operation was continuously conducted over 25 sheets. As a result,sheets could be stuck to wafer without any problems, making it possibleto prepare a conveying cleaning wafer with cleaning function. Further,the cleaning layer was stuck to the mirror surface of a silicon waferover a width of 10 mm, and then measured for 180° peel adhesion withrespect to the silicon wafer according to JIS Z0237. As a result, it was0.018 N/10 mm.

Separately, using a laser surface inspection device, foreign mattershaving a size of 0.2 μm or more on the mirror surface of four sheets ofbrand-new 8 inch silicon wafer were measured. The first sheet showed 6pieces of foreign maters, and the second sheet showed 5 pieces offoreign maters. These wafers were then conveyed into separate substratetreatment devices with an electrostatic attraction mechanism with itsmirror surface facing downward. The mirror surface of these wafers werethen measured for foreign matters having a size of 0.2 μm or more by thelaser surface inspection device. The first and second sheets showed33,456 and 36,091 pieces of foreign matters, respectively, in an area ofthe 8 inch wafer size.

Subsequently, the second release film on the cleaning layer side waspeeled off the conveying cleaning wafer thus obtained. The cleaningwafer was then conveyed over the aforementioned substrate treatmentdevice having the wafer stage to which 33,456 pieces of foreign mattershad been attached. As a result, the cleaning wafer could be conveyedwithout any troubles. Thereafter, a brand-new 8 inch silicon wafer wasconveyed with its mirror surface facing downward, and then measured forthe occurrence of foreign matters having a size of 0.2 μm or more by alaser foreign matter inspection device. This operation was effected fivetimes. The percent removal of foreign matters are set forth in Table4-1.

Comparative Example 4-1

A cleaning sheet was prepared in the same manner as in Example 4-1except that the sheet was irradiated with an ultraviolet ray having acentral wavelength of 365 nm at an integrated dose of 1,000 mJ/cm² inthe atmosphere with the first release film left unpeeled off thecleaning layer. The second release film was then peeled off the cleaninglayer of this cleaning label sheet. The cleaning label sheet was thenstuck to a 8 inch silicon wafer in such an arrangement that the cleaninglayer comes in contact with the wafer. The cleaning label sheet was thenpeeled off the wafer. The surface of the 8 inch silicon wafer was thenmeasured by a laser type foreign matter measuring instrument. As aresult, the number of foreign matters having a size of 0.2 μm or morewas 6,264. A cleaning wafer was then obtained from this cleaning sheetin the same manner as in the example.

Subsequently, the second release film on the cleaning layer side waspeeled off the conveying cleaning wafer thus obtained. The cleaningwafer was then conveyed over the aforementioned substrate treatmentdevice having the wafer stage to which 36,091 pieces of foreign mattershad been attached. As a result, the cleaning wafer could be conveyedwithout any troubles. Thereafter, a brand-new 8 inch silicon wafer wasconveyed with its mirror surface facing downward, and then measured forthe occurrence of foreign matters having a size of 0.2 μm or more by alaser foreign matter inspection device. This operation was effected fivetimes. The percent removal of foreign matters are set forth in Table4-1.

Comparative Example 4-1

A cleaning sheet was prepared in the same manner as in Example 4-1except that the cleaning sheet was not irradiated with an ultravioletray having a central wavelength of 365 nm at an integrated dose of 1,000mJ/cm². This cleaning sheet was then cut by punching into a circlehaving a diameter of 200 mm in the same manner as in Example 4-1 toprepare a label sheet with cleaning function. During this procedure, thecleaning layer didn't yet cure and thus acted as a cushioning material.Thus, since punching couldn't be conducted to a uniform depth, muchmalpunching of label occurred. Further, the label thus prepared wasobserved. As a result, the adhesive was observed to have protruded fromthe end of the label. Moreover, there was observed on the label muchstain of adhesive due to roping of adhesive developed during punching.Further, the adhesive extended and adhered to the second release film onthe cleaning layer side at the end of the label. The label thus preparedwas irradiated with an ultraviolet ray having a central wavelength of365 nm at an integrated dose of 1,000 mJ/cm². However, the adhesive atthe end of the label didn't cure due to oxygen inhibition and stayedadhesive. Accordingly, the preparation of the conveying cleaning waferfrom this label sheet was suspended.

TABLE 4-1 Percent removal of foreign matters 1 sheet 2 sheets 3 sheets 4sheets 5 sheets conveyed conveyed conveyed conveyed conveyed Example 4-180% 88% 90% 92% 92% Comparative 80% 82% 82% 80% 78% Example 4-1Comparative Cleaning suspended Example 4-2

INDUSTRIAL APPLICABILITY

As mentioned above, in the first invention, by predetermining thecleaning layer surface protective film (separator) of the cleaning sheetsuch that the amount of silicone attached to said cleaning layer whenthe cleaning layer surface protective film is peeled off the cleaninglayer or the coated amount of silicone on the separator is not greaterthan a specified value, the cleaning sheet can be applied to a processfor the removal of foreign matters from the conveying site, etc. in asubstrate treatment device to prevent a problem of contamination in thedevice due to protective film and give a high capacity of removingforeign matters.

Further, in the second invention, by forming the cleaning layer surfaceprotective film (separator) of the cleaning sheet by a polyolefin-basedresin which has not been release-treated and arranging such that theamount of heat deterioration inhibitor and lubricant incorporated in thesurface protective film is not greater than a specified value, thecleaning sheet can be applied to a process for the removal of foreignmatters from the conveying site, etc. in a substrate treatment device toprevent a problem of contamination in the device due to protective filmand give a high capacity of removing foreign matters.

Moreover, the label sheet with cleaning function of the third inventioncan provide a label sheet with cleaning function which is not subject topeeling of cleaning label off separator and exhibits a high agestability as well as a cleaning conveying member which can be certainlyconveyed through a substrate treatment device to simply and certainlyremove foreign matters attached to the interior of the device.

Further, in accordance with the process for the production of labelsheet with cleaning function of the fourth invention, a cleaning labelsheet which is not subject to malpunching during sheet punching intolabel form and causes no stain of adhesive can be produced. At the sametime, a label sheet with cleaning function which can be certainlyconveyed through a substrate treatment device to simply and certainlyremove foreign matters attached to the interior of the device.

1. A cleaning sheet comprising: a cleaning layer; and a protective filmcomprising a polyolefin resin, a heat deterioration inhibitor and alubricant, the protective film being provided as a separator on at leastone side of the cleaning layer, and the protective film being nottreated with a releasing agent, wherein a total amount of the heatdeterioration inhibitor and the lubricant is less than 0.01 parts byweight based on 100 parts by weight of the polyolefin resin.
 2. Acleaning sheet comprising: a cleaning layer; a protective filmcomprising a polyolefin resin, a heat deterioration inhibitor and alubricant, the protective film being provided as a separator on one sideof the cleaning layer, and the protective film being not treated with areleasing agent; and an adhesive layer provided on the other side of thecleaning layer, wherein a total amount of the heat deteriorationinhibitor and the lubricant is less than 0.01 parts by weight based on100 parts by weight of the polyolefin resin.
 3. A cleaning sheetcomprising: a backing; a cleaning layer provided on at least one side ofthe backing; and a protective film comprising a polyolefin resin, a heatdeterioration inhibitor and a lubricant, the protective film beingprovided as a separator on the cleaning layer, and the protective filmbeing not treated with a releasing agent, wherein a total amount of theheat deterioration inhibitor and the lubricant is less than 0.01 partsby weight based on 100 parts by weight of the polyolefin resin.
 4. Acleaning sheet comprising: a backing; a cleaning layer provided on oneside of the backing; an adhesive layer provided on the other side of thebacking; and a protective film comprising a polyolefin resin, a heatdeterioration inhibitor and a lubricant, the protective film beingprovided as a separator at least on the cleaning layer, and theprotective film being not treated with a releasing agent, wherein atotal amount of the heat deterioration inhibitor and the lubricant isless than 0.01 parts by weight based on 100 parts by weight of thepolyolefin resin.
 5. The cleaning sheet according to any one of claims 1to 4, wherein the protective film does not comprise the heatdeterioration inhibitor and the lubricant.
 6. A cleaning sheetcomprising: a cleaning layer; and a protective film treated with areleasing agent comprising a silicone, the protective film beingprovided as a separator on at least one side of the cleaning layer,wherein the separator has a silicone coated in an amount of less than0.1 g/m² as calculated in terms of polydimethylsiloxane, wherein anamount of silicone attached to the cleaning layer when the separator ispeeled off from the cleaning layer is 0.005 g/m² or less as calculatedin terms of polydimethylsiloxane, and wherein the tensile modulus of thecleaning layer according to the JIS K7127 method is 10 MPa or more, andwherein the 180° peel adhesion of the cleaning layer with respect to asilicon wafer is 0.010 to 0.20 N/10 mm according to the JIS Z0237method.
 7. The process according to claim 6, wherein the cleaning layercomprises an adhesive which is polymerized and is cured by an activationenergy.
 8. A cleaning sheet comprising: a cleaning layer; a protectivefilm treated with a releasing agent comprising a silicone, theprotective film being provided as a separator on one side of thecleaning layer; and an adhesive layer provided on the other side of thecleaning layer, wherein the separator has a silicone coated in an amountof less than 0.1 g/m² as calculated in terms of polydimethylsiloxane,wherein an amount of silicone attached to the cleaning layer when theseparator is peeled off from the cleaning layer is 0.005 g/m² or less ascalculated in terms of polydimethylsiloxane, and wherein the tensilemodulus of the cleaning layer according to the JIS K7127 method is 10MPa or more, and wherein the 180° peel adhesion of the cleaning layerwith respect to a silicon wafer is 0.010 to 0.20 N/10 mm according tothe JIS Z0237 method.
 9. The process according to claim 8, wherein thecleaning layer comprises an adhesive which is polymerized and is curedby an activation energy.
 10. A cleaning sheet comprising: a backing; acleaning layer provided on at least one side of the backing; and aprotective film treated with a releasing agent comprising a silicone,the protective film being provided as a separator on the cleaning layer,wherein the separator has a silicone coated in an amount of less than0.1 g/m² as calculated in terms of polydimethylsiloxane, wherein anamount of silicone attached to the cleaning layer when the separator ispeeled off from the cleaning layer is 0.005 g/m² or less as calculatedin terms of polydimethylsiloxane, and wherein the tensile modulus of thecleaning layer according to the JIS K7127 method is 10 MPa or more, andwherein the 180° peel adhesion of the cleaning layer with respect to asilicon wafer is 0.010 to 0.20 N/10 mm according to the JIS Z0237method.
 11. The process according to claim 10, wherein the cleaninglayer comprises an adhesive which is polymerized and is cured by anactivation energy.
 12. A cleaning sheet comprising: a backing; acleaning layer provided on one side of the backing; an adhesive layerprovided on the other side of the backing; and a protective film treatedwith a releasing agent comprising a silicone, the protective film beingprovided as a separator at least on the cleaning layer, wherein theseparator has a silicone coated in an amount of less than 0.1 g/m² ascalculated in terms of polydimethylsiloxane, wherein an amount ofsilicone attached to the cleaning layer when the separator is peeled offfrom the cleaning layer is 0.005 g/m² or less as calculated in terms ofpolydimethylsiloxane, wherein the tensile modulus of the cleaning layeraccording to the JIS K7127 method is 10 MPa or more, and wherein the180° peel adhesion of the cleaning layer with respect to a silicon waferis 0.010 to 0.20 N/10 mm according to the JIS Z0237 method.
 13. Theprocess according to claim 12, wherein the cleaning layer comprises anadhesive which is polymerized and is cured by an activation energy. 14.A conveying member with cleaning function comprising a conveying member,a cleaning sheet according to any one of claims 8, 12, 2 and 4 providedon the conveying member with an adhesive layer interposed therebetween.15. A process for cleaning a substrate treatment device, the processcomprising: peeling off the protective film of the cleaning sheetaccording to any one of claims 6, 10, 1 and 3 or the conveying memberaccording to claim 14; and conveying the cleaning sheet or the conveyingmember into a substrate treatment device after the peeling.
 16. A labelsheet with cleaning function comprising: a backing; a cleaning layerprovided on one side of the backing; a release film provided on thecleaning layer; a separator; and an at least one adhesive layer providedon the other side of the backing, and provided on the separator at acondition that the separator is capable of being peeled off from theadhesive layer, wherein at least one of the adhesive layers arecontinuously provided apart from each other on one separator, 180° peeladhesion required to peel off the separator from the adhesive layer is0.05 N/50 mm or more, and wherein the tensile modulus of the cleaninglayer according to the JIS K7127 method is 10 MPa or more, and whereinthe 180° peel adhesion of the cleaning layer with respect to a siliconwafer is 0.010 to 0.20 N/10 mm according to the JIS Z0237 method. 17.The label sheet with cleaning function according to claim 16, whereinthe cleaning layer comprises a curing adhesive comprising: apressure-sensitive adhesive polymer; a polymerizable unsaturatedcompound having one or more unsaturated double bonds per molecule; and apolymerization initiator.
 18. The label sheet with cleaning functionaccording to claim 16, wherein the cleaning layer comprises a curingadhesive comprising: a pressure-sensitive adhesive polymer; apolymerizable unsaturated compound having one or more unsaturated doublebonds per molecule; and a polymerization initiator, and thepressure-sensitive adhesive is an acrylic polymer comprising a(meth)acrylic acid alkylester.
 19. The label sheet with cleaningfunction according to claim 16, wherein the cleaning layer comprises acuring adhesive comprising: a pressure-sensitive adhesive polymer; apolymerizable unsaturated compound having one or more unsaturated doublebonds per molecule; and a polymerization initiator, and thepolymerization initiator is a photopolymerization initiator and thecleaning layer is a photo-curing adhesive layer.
 20. The processaccording to claim 16, wherein the cleaning layer comprises an adhesivewhich is polymerized and is cured by an activation energy.
 21. A processfor the production of a label sheet with cleaning function, the processcomprising: providing a cleaning layer on one side of a backing, thecleaning layer having a release film at a surface thereof, and thecleaning layer comprising an adhesive which is polymerized and is curedby an activation energy; and providing at least one adhesive layerbetween the backing and a separator at a condition that the separator iscapable of being peeled off from the at least one adhesive layer, the atleast one adhesive layer being on the other side of the backing; peelingoff a first release film from the cleaning layer before the polymerizingand curing of the adhesive; subjecting the cleaning layer to thepolymerizing and curing under a condition that there are no substantialeffect of oxygen; protecting a surface of the cleaning layer by a secondrelease film after the subjecting; and punching the obtained laminate ofthe cleaning layer, the backing, the adhesive layer and the secondrelease film into a label form, wherein an amount of foreign mattershaving a size of 0.2 μm or more transferred from the cleaning layer to asilicon wafer is 20 pieces/in² or less, wherein the tensile modulus ofthe cleaning layer during the punching according to JIS K7127 testingmethod is 10 MPa or more, and wherein the 180° peel adhesion of thecleaning layer with respect to a silicon wafer is 0.010 to 0.20 N/10 mmaccording to the JIS Z0237 method.
 22. The process according to claim21, wherein the first release film is a film with a releasing agentcomprising a silicone.
 23. The process according to claim 21, whereinthe cleaning layer comprises a curing adhesive comprising: apressure-sensitive adhesive polymer; a polymerizable unsaturatedcompound having one or more unsaturated double bonds per molecule; and apolymerization initiator.
 24. The process according to claim 23, whereinthe pressure-sensitive adhesive polymer is an acrylic polymer comprisingat least one of a (meth)acrylic acid and a (meth)acrylic acidalkylester.
 25. The process according to claim 23, wherein thepolymerization initiator is a photopolymerization initiator and thecleaning layer is a photo-curing adhesive layer.
 26. The processaccording to claim 21, wherein at least one of the adhesive layers arecontinuously provided apart from each other on a separator.